It is common for a flat roof, that is a roof having a surface that is substantially horizontal, to support various other structures such as air conditioners, heaters, signage, vents, stacks, and so forth. One of the most common members that extend through the surface of a flat roof is a pipe, and such pipes are available in certain predetermined inner diameters.
To seal a pipe extending through a roof against the leakage of water under a layer of roofing material applied to the surface of the roof, a pipe boot is provided. The pipe boot is made of a somewhat elastomeric material such as a vinyl, a rubber, or the like. The boot includes an upper portion that consists of a plurality of concentric generally cylindrical tubular portions stacked in descending diameters with a radial flange extending outwardly of the tubular portion having the largest diameter. The inner diameters of the tubular portions are chosen to fit around the outer diameter of commonly used pipe sizes.
To employ a pipe boot to seal a length a pipe extending through a roof and prevent water from getting under the roofing material applied to the surface of the roof, the pipe boot is cut to remove the stacked tubular portions that are smaller in diameter than that needed to fit around the given pipe. The boot is therefore cut to provide an opening that will fit snugly around the outer diameter of the pipe. Thereafter, the pipe boot is fitted over the length of pipe with the radial flange bonded to the roofing material applied to the surface of the roof. A hose clamp is then wrapped around the tubular portion that snuggly receives the pipe and tightened to provide a hermetical seal.
To provide a good seal around a pipe, it is desirable that the tubular portion fitted around the length of pipe have sufficient axial length to receive a hose clamp such that it will not slip off the end of the tubular portion over a period of time. It is therefore desirable that the cut to remove the smaller stacked diameters of tubular portions be made as near as possible to the annular flange that separates the tubular portion of the desired diameter from tubular portions of smaller diameters. Typically, the pipe boot is cut by a roofer at the site, and often the roofer inadvertently destroys the pipe boot because of the difficulty of providing an accurate cut that allows sufficient axial length of the desired tubular portion to receive a hose clamp. It would be desirable therefore to provide an improved pipe boot that could be more easily cut to the desirable size by a roofer working in the field.